AVCHD to AMR Converter

AVCHD to AMR: Choose the Audio Codec Before You Press Convert

This is the one conversion on the site where the single most important thing you can do is not accept the defaults. The Audio Codec list on this page opens with nothing selected, and if you leave it that way on an AVCHD source the job fails and hands back an empty file. Choose AMR Narrow Band or AMR Wide Band explicitly and everything works. The rest of this page explains why, so you can recognise the symptom rather than guessing at it.

The conversion itself is simple in principle: an AVCHD recording is an MPEG-2 transport stream carrying H.264 video next to a Dolby Digital (AC-3) or linear-PCM soundtrack, and AMR is the 3GPP speech format phones used for voice notes and MMS. You are throwing away the picture and squeezing a 48 kHz camcorder soundtrack down to a mono narrowband or wideband speech codec. That is a drastic step, and worth doing only when something specifically wants .amr.

How to Convert AVCHD to AMR

1. Upload Your AVCHD File: Drag the .avchd onto the page or click "+ Add Files". Only the .avchd extension is accepted here. The video track is discarded on the server; only the audio is converted.
2. Pick AMR Narrow Band or AMR Wide Band: Open Audio Codec and select one. This is not optional — see the section below. Narrow Band encodes mono at 8 kHz, Wide Band mono at 16 kHz, and choosing either one makes the pipeline apply that codec's channel and sample-rate rules for you.
3. Leave File Compression Alone, or Understand What It Does: File Compression offers Quality Preset and Constant Bitrate. Both end up at the same place on AMR — the codec's top mode — for the reasons set out in the table below. Trim takes a Start time and a Duration if you only want a section.
4. Convert and Download: Click Convert and save the .amr. Files are uploaded over an encrypted connection, decoded and re-encoded on our servers, and deleted automatically after a few hours — no sign-up, no watermark, never shared or made public.

Why an Untouched Audio Codec Fails Here

The page applies a default that names the codec family, "AMR", rather than one of the two encoders. That value matches no entry in the rendered list, so nothing appears selected, and it matches no key in the conversion pipeline's codec table either. The knock-on effect is that the codec's own constraints — mono only, one fixed sample rate — are never applied, and the encoder is instead chosen from the requested sample rate: 8000 Hz picks the narrowband encoder, anything else picks the wideband one.

An AVCHD soundtrack is 48 kHz and normally stereo, so with the codec left alone that logic sends 48 kHz stereo audio to a wideband encoder that only accepts 16 kHz mono. Here is what each combination actually does, all reproduced on a 6-second AVCHD test file with a 48 kHz stereo AC-3 track:

The two bottom rows are the point. Once you name a codec, the pipeline knows its rules and clamps the channel count to mono and the sample rate to the codec's fixed value on your behalf, so nothing you do in the other two dropdowns can break the job. There is also a visible symptom you can use as a check: with the codec untouched, opening Constant Bitrate shows an empty dropdown. Pick a codec and eight rungs (narrowband) or nine (wideband) appear.

Narrow Band or Wide Band, and Why the Bitrate Rungs All Land in the Same Place

That "mode you will actually get" row is not a simplification. The rungs in the dropdown are labelled with decimal values such as 4.75KBPS and 23.85KBPS, and the code that turns a rung into a number keeps only the digits — so 4.75KBPS becomes 475 kbps and 23.85KBPS becomes 2,385 kbps. Both are far above what AMR can do, so both are clamped back to the codec's ceiling, and the encoder then reports what it settled on: bitrate not supported: use one of 4.75k, 5.15k, 5.90k, 6.70k, 7.40k, 7.95k, 10.20k, 12.20k, using 12.20k. Quality Preset arrives at the same ceiling by a different route. The practical consequence is simple — your only real quality lever on this page is Narrow Band versus Wide Band, and for camcorder audio Wide Band is almost always the better answer.

Frequently Asked Questions

My camcorder files are named .MTS, not .avchd. Can I use this page?

Not directly — this page accepts the .avchd extension only. No camcorder actually writes .avchd: the AVCHD specification stores clips as .MTS on the memory card and as .M2TS once they have been imported into a BDMV folder structure or onto a disc, so a file literally named .avchd has almost always been produced by a converter or renamed by hand. Use MTS to AMR for files straight off a card or M2TS to AMR for the imported spelling. A .avchd and a .mts hold byte-identical transport-stream data, so renaming works, but using the page that matches your filename is one less thing to get wrong.

Why would anyone convert camcorder footage to AMR at all?

Because something on the other end demands it. AMR is the 3GPP speech format that feature phones used for voice memos and MMS attachments, and it still turns up as the required upload format for older telephony systems, voicemail platforms, some IVR and dictation tools, and a handful of embedded devices. It is a speech codec, not a music codec — it models a human vocal tract — so the only sensible content for it is talking. If you want the audio for listening, AVCHD to MP3 is a far better use of the same bytes, and AVCHD to WAV keeps every sample.

Will the camcorder's Dolby Digital audio survive?

It is decoded and re-encoded, not copied — AMR cannot carry AC-3 and nothing on this route passes a stream through untouched. AVCHD recordings that used linear PCM instead go through the same decode. Whatever the source layout was, the result is mono: AMR has no stereo mode at all, so a 2.0 or 5.1 camcorder track is downmixed on the way in. Because AMR is tuned for speech, ambient sound, music and handling noise from the camcorder will come back sounding far worse than dialogue does.

What happens if my AVCHD file has no audio track?

The job fails and no file is written. An audio-only target with nothing to encode produces the error "Output file does not contain any stream" rather than a silent .amr, which is the right behaviour but can look like a fault. Check the source in a player first — a .avchd produced by demuxing only the video from a camcorder clip is the usual explanation.

Which sample rates does the Audio Sample Rate dropdown offer, and do they matter?

On this page the list is trimmed to just 8000 HZ and 16000 HZ, because those are the only two rates the AMR family defines. If you have selected a codec, the choice is redundant: Narrow Band is forced to 8 kHz and Wide Band to 16 kHz regardless of what the dropdown says. If you have not selected a codec, the dropdown becomes load-bearing in the worst way — it decides which encoder gets picked, and any value other than 8000 sends your 48 kHz stereo source to the wideband encoder, which rejects it. Select a codec and the problem disappears.

Why does the Audio Channel dropdown only offer MONO?

Because AMR has no other option, and the page hides ORIGINAL and STEREO accordingly. Nothing is preselected, though, which is why an untouched page still sends the source's real channel count to the encoder — and why an untouched codec plus a stereo source fails with Only mono supported. Selecting a codec is again the fix, because the pipeline then downmixes to mono for you before the encoder ever sees the audio.

How big will the AMR file be?

Very small, and almost perfectly predictable, because AMR runs at a fixed mode. Our measured 6-second clip came back as 9,670 bytes from Narrow Band and 18,370 bytes from Wide Band, which works out at roughly 97 KB per minute for narrowband and 184 KB per minute for wideband. A one-hour AVCHD recording therefore becomes about 5.8 MB or 11 MB of AMR. If you only need a section, use Trim rather than converting the whole recording.

Can I play an .amr file on a computer?

Some players handle it and many do not — AMR support was built for handsets rather than desktops, so VLC and ffmpeg-based tools open it while several stock media players and browsers do not. That is worth checking before you build a workflow around the format. If the recipient's software cannot open AMR, ask whether they can take an MP3 or a WAV instead; if they genuinely need AMR, tell them whether you sent narrowband or wideband, since a few older systems only accept the narrowband variant.

How long are my files kept on the server?

Uploads travel over an encrypted connection, are converted on our servers, and both the upload and the output are deleted automatically after a few hours. Nothing is shared or made public, no account is required, and no watermark is added. AVCHD recordings are large — the format records at up to 24 Mbit/s — so a long clip takes real time to upload before any conversion starts, and upload speed rather than any cap on our side is what limits the file size you can practically send.